According to a general form of controlling an actuator for driving loads, a controller transmits a driving command to a driver corresponding to the actuator and the driver controls the driving of the actuator according to the command. However, in such an actuator driving form, controllers are disposed in respective actuators, and a control program for the actuator is set in each controller. Thus, the more the number of actuators to be driven, the larger the labor paid to establishment of the control system.
Thus, a technique for establishing a system for controlling the driving of a plurality of actuators has been developed. For example, in a system disclosed in Patent Document 1, intelligent motors (controller-integrated motors) are connected in series, and an uppermost intelligent motor is connected to a control unit that can connect to an external network. The system is configured such that the uppermost intelligent motor serves as a master motor to receive control information on the subject motor and the other motors from the control unit, and the control information can be transmitted to the other motors via series-connected signal lines. This system includes a “unit control mode” in which the control unit directly controls the master motor and indirectly controls the other motors with the aid of the master motor and a “self-control mode” in which the respective motors other than the master motor is operated by the master motor in a state where the control unit is separated from the master motor.